1. Field of the Invention
The present invention relates to a combination light and air ventilation fixture, and more particularly to such a fixture having a surrounding support frame, which is constructed primarily out of stamped metal formations, for use in a suspended ceiling grid system.
2. Description of the Prior Art
Suspended ceiling systems are extensively used throughout the construction industry, both in new building construction and in the renovation of older buildings. A suspended ceiling consists of a grid-like support base suspended from the "true" ceiling, the base supporting a layer of ceiling panels, typically acoustical tile. In addition, the suspended grid frequently serves as a support base for the lighting fixtures and heating and air conditioning outlet ducts. The available space between the true ceiling and the false or suspended ceiling enables the economical placement of the air ventilation ductwork required to supply the individual ducts in comparison to the previously utilized floor and/or wall constructions.
For many years after the introduction of forced-air heating and cooling systems, the ceiling ducts were essentially individual louvered openings located in the ceiling. These openings typically formed arrays corresponding to the location of the (sometimes hidden) ventilation ductwork. Incandescent light bulbs and their associated fixtures did not lend themselves toward the utilization of combined lighting and air ventilation systems. However, with the advent of fluorescent lighting, architects were provided with numerous large, rectangular ceiling light fixtures, with sufficient surface area to make concurrent usage for air ventilation practicable.
In some of these early combination fixtures, the forced air was introduced directly into the light reflection area with it exhausting into the room through the open bottom of the light fixture. Later, when the light fixtures were provided with translucent panels to help diffuse the light, air gaps were left along the sides of the panels to permit the discharge of the air into the room. In a slightly different construction, such light and air fixtures were provided with an outer covering or hood which surrounded the light reflection unit and created a passageway for the airflow. The hood portion terminated at the bottom of the light fixture, creating a surrounding, spaced border through which the air is discharged into the room. These fixtures could alternatively function as an air exhaust vent, removing air. The next progression found these fixtures providing the capability for complete air ventilation, both forced air supply and exhaust, in the same lighting fixture. Various baffles and plenums were used to segregate the two air streams. A lateral opening along each side of the fixture was provided, one for discharging air into the room and the other for exhausting it from the room. With the baffles and separate air passageways, these normally unitized lighting fixtures were somewhat complex in manufacture. In addition to their complexity, there normally was also an aesthetic requirement for a surrounding border construction for the fixture installation, complementing the two, lengthy lateral air openings. This resulted in additional labor requirements during installation.